Laboratory Services 
Understanding New Fuel Technology
Biodiesel
Biodiesel is a mixture of fatty acid alkyl esters made from vegetable oils, animal fats or recycled greases. Biodiesel can be used as a fuel for vehicles in its pure form, but it is usually used as a petroleum diesel additive to reduce levels of particulates, carbon monoxide, hydrocarbons and air toxics from diesel-powered vehicles. Check out What is Renewable Diesel? for more information on biodiesel.
Biodiesel Feedstocks
In the United States, most biodiesel is made from soybean oil or recycled cooking oils. Animals fats, other vegetable oils, and other recycled oils can also be used to produce biodiesel, depending on their costs and availability. In the future, blends of all kinds of fats and oils may be used to produce biodiesel.
Biodiesel Production
Key Reaction. The main reaction for converting oil to biodiesel is called transesterification. The transesterification process reacts an alcohol (like methanol) with the triglyceride oils contained in vegetable oils, animal fats, or recycled greases, forming fatty acid alkyl esters (biodiesel) and glycerin. The reaction requires heat and a strong base catalyst, such as sodium hydroxide or potassium hydroxide. The simplified transesterification reaction is shown below.
Transesterification
Transesterification of neutral oils is carried out both for the purpose of producing bio-diesel or methyl esters for different purposes as MES. The process is fully continuous and, in the case of bio-diesel, can also accept as part of the feed low grade materials as UFO (Used Frying Oils) or greases.
The unit includes a glycerine treatment section that gives high quality crude glycerine.
Pretreatment Reaction — Esterification
Some feedstocks must be pretreated before they can go through the transesterification process. Feedstocks with less than 4% free fatty acids, which include vegetable oils and some food-grade animal fats, do not require pretreatment. Feedstocks with more than 4% free fatty acids, which include inedible animal fats and recycled greases, must be pretreated in an acid esterification process. In this step, the feedstock is reacted with an alcohol (like methanol) in the presence of a strong acid catalyst (sulfuric acid), converting the free fatty acids into biodiesel. The remaining triglycerides are converted to biodiesel in the transesterification reaction.